where the xijxij can be interpreted as quantities of goods sent from source ii to destination jj, for i = 1,2, … ,mai=1,2,…,ma and j = 1,2, … ,mbj=1,2,…,mb, at a cost of cijcij per unit, and it is assumed that ∑ imaAi = ∑ jmb∑jBj∑imaAi=∑jmb∑jBj and xij ≥ 0xij≥0.